The primary objective of this proposal is to develop more effective treatment and prophylaxis of ocular infections by sustaining the ocular surface residence and release of a broad spectrum antibiotic agent. This Phase I proposal involves selecting the appropriate combination of polymers and other vehicle excipients to form a sustained release formulation compatible with a broad spectrum drug such as tobramycin, an anti-infective drug already approved for use in the eye. Published research has demonstrated that infections are more rapidly controlled when an effective antibiotic concentration at the target site can be maintained, rather than by administering drug repeatedly as with standard eyedrops. Less frequent dosing also improves patient compliance with the drug regimen. Indications of safety and efficacy of the formulation to be developed in animals should allow for relatively rapid progression to studies in humans for treatment of moderate-severe infections, including those caused by pseudomonas. A sustained-release antibiotic could both speed recovery time and increase the likelihood of restoring the patient's pre-infection level of visual acuity.